Dual clutch transmissions combine certain features of manual and automatic transmissions. In a dual clutch transmission or DCT having oddly-numbered and evenly-numbered gear sets, one of a pair of input clutches is applied to engage any of the oddly-numbered gear sets. Likewise, the other input clutch is applied to engage any of the evenly-numbered gear sets. An onboard transmission controller predicts the next-selected gear using available control inputs such as engine acceleration and braking levels, and then commands an engagement of the next gear ahead of the impending shift. Relative to a conventional transmission, a DCT can provide faster gear shifts, typically with improved shift control and increased power.
The two available input clutches in a wet DCT are cooled and lubricated by transmission fluid circulated via an engine-driven or auxiliary fluid pump. In a dry DCT (dDCT), the various gear sets within a gearbox of the DCT are cooled and lubricated in the same manner while the two input clutches remain dry. As a result, a dDCT may experience a greater amount of temperature-related performance variation relative to a wet DCT.